I work as the Treasurer for a major Fortune 500 firm, which includes a large cross border payments business
The eBay payment processing for transactions can easily be done within less than 30 minutes (especially given that they are small value payments).
The long eBay processing has nothing to do with security checks (since 99% of transactions are between existing customers nor does it have anything to do with external intermediaries like PayPal, Visa, Mastercard etc).
By holding payments from sellers to buyers for short periods of time, effectively gives eBay free money and allows eBay to earn additional interest income (and a lot of it).
According to the most recent eBay Financials, eBay has on average 2 billion transactions per day, which equates to over 500 billion transactions per year.
Assuming the average transaction amount + the cost of postage is $10 (it could be a little less or even a lot more), but at $10 per transaction it means that eBay is holding $20 billion of cash on average in its bank accounts every single day because of this so called "payments processing". And because it is being done on a rolling basis (i.e., when eBay payout $20 billion to sellers 24 hours after receiving the money from buyers, it is simply replaced by the next day's $20 billion of payments from buyers, which will be held by eBay for at least 24 hours).
As such, eBay is effectively using money that technically belongs to the sellers as free money and earning interest on it.. all without compensating the sellers for these short term loans that they provide eBay.
A simple calculation shows that the additional interest earned by eBay from holding the funds for just 1 extra day is material. If interest rates are at 5%, eBay earns an additional $1 billion per year in interest by delaying payments to buyers for just a single day.
Sellers will notice eBay has no payment processing time issues when it comes to taking listing fees or advertising fees from buyers upon a sale. These funds are taken immediately.
Buyers will also notice that oddly eBay has no payment processing time issues when it comes to taking payments for goods purchased. Such payments are moved instantly from the bank accounts of buyers to an eBay bank account.
It's just when money has to be moved from an eBay bank account when suddenly it takes eBay time to process payments.
As mentioned, I work as the Treasurer of a major listed company with nearly $100 billion in revenue, and deal with more than a 100 currencies both at an institutional level and at a retail level, and for retail payments (which is what eBay deals in), there should be no payment processing delays for small value payments (i.e., less than a million dollars per transaction).
Hope that helps.
